Information processing apparatus and information processing method

ABSTRACT

According to at least one embodiment, an information processing apparatus includes: a content acquiring module configured to receive or store a content according to a first copyright protection method; a filter configured to acquire PIDs from first packets of the content; an analyzing module configured to acquire a PAT/PMT from each of the PIDs; a generating module configured to generate a PMT based on the PAT/PMT according to a second copyright protection method; encrypters configured to encrypt PES payloads by managing independent sets of an encryption key and an initial vector for the respective PIDs; and a packet generating module configured to generate second packets based on encryption results.

CROSS REFERENCE TO RELATED APPLICATION(S)

The application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2011-194407 filed on Sep. 6, 2011, andNo. 2012-025600 filed on Feb. 8, 2012, the entire contents of each ofwhich are incorporated herein by reference.

BACKGROUND

1. Field

The present invention relates to an information processing apparatus andan information processing method.

2. Description of the Related Art

There is a use form in which a PC picture is displayed on the screen ofanother apparatus such as a TV receiver through a Wi-Fi connection. Ingeneral, the entire picture is encoded again in the PC, also in the caseof a copyright-protected content. This results in quality degradation ofthe content and delay due to the re-encoding.

BRIEF DESCRIPTION OF THE DRAWINGS

A general configuration that implements the various features ofembodiments will be described with reference to the drawings. Thedrawings and the associated descriptions are provided to illustrateembodiments and not to limit the scope of the embodiments.

FIG. 1 shows the configuration of a copyright protection systemaccording to a first embodiment of the present invention;

FIG. 2 shows a transport stream that is received according to a firstcopyright protection method in the first embodiment;

FIG. 3 shows a transport stream that is sent according to a secondcopyright protection method in the first embodiment;

FIG. 4 is a flowchart of a copyright protection method conversionprocess which is executed by a first content receiver according to thefirst embodiment;

FIG. 5 is a flowchart of a process for generating TS packet data thatcomply with the second copyright protection method, the process beingexecuted by the first content receiver according to the firstembodiment;

FIG. 6 is a data flow diagram of content data in the first contentreceiver according to the first embodiment;

FIG. 7 shows a network which is formed between the informationprocessing apparatus according to the first embodiment;

FIG. 8 shows the internal configuration of a cell phone which is aninformation processing apparatus according to the first embodiment; and

FIG. 9 shows the configuration of a copyright protection systemaccording to a second embodiment.

DETAILED DESCRIPTION

According to one embodiment, an information processing apparatusincludes: a content acquiring module configured to receive or store acontent according to a first copyright protection method; a filterconfigured to acquire PIDs from first packets of the content; ananalyzing module configured to acquire a PAT/PMT from each of the PIDs;a generating module configured to generate a PMT based on the PAT/PMTaccording to a second copyright protection method; encrypters configuredto encrypt PES payloads by managing independent sets of an encryptionkey and an initial vector for the respective PIDs; and a packetgenerating module configured to generate second packets based onencryption results.

Embodiments of the present invention will be hereinafter described.

(Embodiment 1)

A first embodiment will be described below with reference to FIGS. 1-8.FIG. 1 shows the configuration of a copyright protection systemaccording to the first embodiment.

A content server S sends content data provided by a VOD (video ondemand) service or an IPTV service to a first content receiver A via theInternet or a CDN (contents delivery network).

The content data provided by the VOD (video on demand) service or IPTVservice is in the MPEG2-TS (transport stream) form in which a PES(packetized elementary stream) header and a PES payload are divided intoplural TS packets. As shown in FIG. 2, the TS payloads areAES-CBC-encrypted according to a first copyright protection method. Anencryption key for content data is determined by the content server S,and transferred from the content server S to the first content receiverA through authentication and key exchange processing which are performedbetween the content server S and the first content receiver A accordingto a method that complies with the first copyright protection methodbefore the content server S sends the content data to the first contentreceiver A.

The first content receiver A, which is a PC, a tablet terminal, an STB,or the like, decrypts and decodes content data that has been receivedfrom the content server S and is encoded according to the firstcopyright protection method, and displays resulting content data on thescreen. The first content receiver A sends the received content data toa second content receiver B by Wi-Fi or a method described later.

The first embodiment will be described in detail with reference todrawings showing hardware etc.

FIG. 7 shows a network which is formed between information processingapparatus according to the invention. In the first embodiment, a localnetwork is formed between a cell phone 1 (content receiver A) which canbe used as an information processing apparatus according to theinvention and a TV receiver 2 (content receiver B; not shown) which canbe used as an information processing apparatus according to theinvention. Although the following description will be directed to thecase that the cell phone 1 and the TV receiver 2 are used as informationprocessing apparatus, the cell phone 1 may be replaced by any of theabove-mentioned apparatus.

The cell phone 1 exchanges voice data or other data with a base station3 of a mobile communication network according to a communication methodsuch as W-CDMA. The base station 3 is connected to the Internet 5 via aprescribed public network. A server 6 (content server S) is connected tothe Internet 5. The TV receiver 2 can communicate with the cell phone 1using a WLAN (wireless LAN) communication module, for example. From theview point of current consumption, it is preferable that a wirelesscommunication be performed between the cell phone 1 and the TV receiver2 which are distant from each other by about several meters. Thisconfiguration enables a data transfer in which first the cell phone 1performs a data communication with the server 6 via the base station 3,then the cell phone 1 establishes a connection to the TV receiver 2using a WLAN communication module incorporated in the cell phone 1, andfinally the cell phone 1 transfers, to the TV receiver 2, data that istransmitted via the base station 3.

FIG. 8 shows the internal configuration of the cell phone 1 which can beused as an information processing apparatus according to the invention.A configuration for realizing a wireless communication between the cellphone 1 and the TV receiver 2 (another information processing apparatus)will mainly be described with reference to FIG. 8 and a detaileddescription of a general configuration of the cell phone 1 willbasically be omitted. The cell phone 1 is equipped with a cell phonewireless communication module 11, a WLAN communication module 13, a CPU15, a memory 18, an input module 19, and an output module 20 which areconnected to each other by a bus 22.

The cell phone wireless communication module 11 realizes exchange voicedata or other data between cell phone 1 and the base station 3. Providedwith an antenna (not shown), the cell phone wireless communicationmodule 11 receives, from the space, a wireless signal that istransmitted from the base station 3 of the module communication networkby a prescribed communication processing system. And the cell phonewireless communication module 11 emits, from the antenna to the space, awireless signal to be transmitted wirelessly to the base station by theprescribed communication processing system. The cell phone wirelesscommunication module 11 performs prescribed processing on a receivedsignal and then outputs resulting data to the CPU 15 or causes theoutput module 20 (receiver) to output a voice. Furthermore, the cellphone wireless communication module 11 causes transmission of data thatis output from the CPU 15 after being subjected to prescribed processingor a voice picked up by the input module 19 (microphone).

The WLAN communication module 13 performs a wireless LAN communicationthat complies with the communication standard IEEE 802.11a, IEEE802.11b, or the like via a built-in antenna.

The CPU (central processing unit) 15 performs various kinds ofprocessing according to programs stored in the memory 18 (ROM (read-onlymemory)) or various application programs and control programs includingan operating system (OS) that are loaded into a RAM (random accessmemory) from the ROM. The CPU 15 supervises the cell phone 1 bygenerating various control signals and supplies them to the individualmodules. When necessary, the RAM stores data etc. that are necessary forthe CPU 15 to perform various kinds of processing. The memory 18 has anHDD (hard disk drive) or a flash memory which is an electricallyrewritable and erasable nonvolatile memory.

The input module 19 receives an input through an input module havingmanipulation keys or a touch screen and outputs a resulting input signalto the CPU 15. During a voice call, the input module 19 picks up a uservoice through the microphone. The output module 20 outputs a text, animage, etc. according to instructions from the CPU 15. The output module20 is an LCD (liquid crystal display), an organic EL display, or thelike. During a voice call, the output module 20 outputs a voice of acall partner via the receiver.

Content data that is transmitted from the first content receiver A tothe second content receiver B is in the MPEG2-TS form in which a PESheader is stored in one of plural TS packets, and a PES payload isdivided and stored in the plural TS packets. Besides, one PES payload iscorresponding to one PES header in the MPEG2-TS form. Therefore, in theMPEG2-TS form, the PES payload is divided into plural segments, the PESheader and one segment of the PES payload are stored in a packet 1, andother segments of the PES payload are stored in a packet 2 and posteriorpackets, as shown in FIG. 2. The combination of the PES head and the PESpayload, as the above, is repeated in the MPEG2-TS form. However, whendata is transmitted according to the second copyright protection method,unlike in the case of the first copyright protection method, the size ofeach segment of the PES payload in each TS packet should be a multipleof a prescribed size (e.g., 16 bytes) except for the tail segment of thePES payload of TS packets constituting content data. On the other hand,the TS packet size is fixed to, for example, 188 bytes. Therefore, ineach TS packet, an adaptation field padded with stuffing bytes isinserted to occupy a portion other than the PES header and the segmentsof the PES payload, so that the size of each TS packet that consists ofthe TS header, PES header, segment of the PES payload, adaptation field,etc. becomes 188 bytes. As shown in FIG. 3, there are TS packets that donot include a PES header. As shown in FIG. 3, only the segment of thePES payload of each TS payload is AES-CTR-encrypted according to thesecond copyright protection method. For example, a segment of the PESpayload n (n=1, 2, . . . , N) shown in FIG. 2 is divided into segmentsof the PES payload n′ and (n−1)″ shown in FIG. 3.

An encryption key to be used for transmitting content data according tothe second copyright protection method is determined by the firstcontent receiver A, and transferred from the content server S to thefirst content receiver A through authentication and key exchangeprocessing which are performed between the first content receiver A andthe second content receiver B according to a method that complies withthe second copyright protection method before the first content receiverA sends the content data to the second content receiver B.

The second content receiver B, which is a display apparatus such as a TVreceiver, decrypts and decodes content data that has been received fromthe first content receiver A and is encoded according to the secondcopyright protection method, and displays resulting content data on thescreen. The second content receiver B should be compatible with a codecfor content data provided by a VOD service or an IPTV service.

The connection interface between the first content receiver A and thesecond content receiver B may be either a wireless interface other thanWi-Fi or a wired interface such as Ethernet (registered trademark).

For example, the first copyright protection method is Marlin(http://www.marlinusers-japan.org/) and the second copyright protectionmethod is HDCP (high-bandwidth digital content protection) 2.0(http://www.digital-cp.com/).

A process that the first content receiver A receives content data thatis encrypted according to the first copyright protection method,encrypts the received content data according to the second copyrightprotection method, and sends resulting content data to the secondcontent receiver B will be described below. FIGS. 4 and 5 are flowchartsof programs which are run by the CPU 15.

At step S401, authentication and key exchange processing are performedwith the content server S according to the first copyright protectionmethod, whereby a decryption key for content data to be sent from thecontent server S is determined.

At step S402, authentication and key exchange processing are performedwith the second content receiver B according to the second copyrightprotection method, whereby an encryption key and part r_(iv) of aninitial vector for content data to be sent to the second contentreceiver B are determined. In this embodiment, the initial values of theencryption key and the initial vector are kept constant for allelementary streams. However, they may vary from one elementary stream(hereinafter abbreviated as ES) to another depending on the secondcopyright protection method.

If the reception the content data from the content server S has notcompleted yet (S403: no), the first content receiver A receives anMPEG2-TS packet at step S404 and AES-CBC-decrypts the TS payload withthe decryption key at step S405. It is assumed that the initial vectorfor the AES-CBC decryption is kept the same in a service.

At step S406, a PID (packet identification) filter extracts a PID thatis contained in the header of the received packet and identifies thekind of the packet. The initial value of the filtering subject PID is“0x0000” for a PAT and “0x1fff” for a null packet. A filtering subjectPID is added in the following manner.

At step S407, a reception packet counter is incremented by 1. If thereception packet is a PAT (program association table) (S408: yes), atstep S409 a PID of a PMT (program map table) is acquired by analyzingthe PMT. The PMT PID is added as a filtering subject PID of the PIDfilter. At step S410, the reception packet itself is made a transmissionpacket to be transmitted to the second content receiver B. At step S411,a transmission packet counter is incremented by 1. At step S425, thegenerated transmission packet is sent out. Then, the process returns tostep S403.

If the reception packet is a PMT (S412: yes), at step S413 a PID of anES is acquired by analyzing the PMT. The ES BID of video, audio, asubtitle, or the like is added as a filtering subject PID of the BIDfilter. At step S414, a descriptor (e.g., registration_descriptor in thecase of HDCP 2.0) indicating that the content is encrypted according tothe second copyright protection method is added to the received PMT. Atstep S415, a transmission packet to be transmitted to the second contentreceiver B is generated. At step S416, the transmission packet counteris incremented by 1. At step S425, the generated transmission packet issent out. Then, the process returns to step S403.

If the reception packet is an ES (S417: yes), step S418 is executed inthe following manner. At step S501 (see FIG. 5), an initial value “0” isset for the number n of generated TS packet data. Ifpayload_unit_start_indicator of the TS header contained in the receptionpacket is “1,” the reception packet is regarded as containing a PESheader (S502: yes). If the size of the remaining segment of the PESpayload is larger than a size (e.g., 184 bytes) that is set as a size ofa TS packet excluding a header (S503: yes), at step S504 data of 176bytes that is a maximum multiple of 16 (AES-CTR encryption key size)that is smaller than 184 bytes is extracted from the remaining segmentof the PES payload (i.e., data beginning from the head of the remainingsegment of the PES payload) and AES-CTR-encrypted. At step S505, anadaptation field padded with stuffing bytes (8 bytes) is inserted beforethe encrypted segment of the PES payload to generate one TS packet data.At step S506, the number n of generated TS packet data is incrementedby 1. The above steps are repeated (i.e., TS packet data is generatedand the number n of generated TS packet data is incremented by 1) untilthe size of the remaining segment of the PES payload becomes smallerthan 184 bytes (S503: no). If the size of the remaining segment of thePES payload is smaller than or equal to 184 bytes (S503: no), at stepS504′ the entire remaining segment of the PES payload isAES-CTR-encrypted. At step S505′, an adaptation field that is paddedwith stuffing bytes so that the size of a resulting TS packet databecomes 184 bytes is inserted before the encrypted segment of the PESpayload to generate one TS packet data. At step S506′, the number n ofgenerated TS packet data is incremented by 1.

Since a PES header is contained in the reception packet (S502: yes), atstep S507 an AES-CRT encryption key and an initial vector are set forthe ES-PID concerned. In this embodiment, the encryption key is the sameas the initial value. For example, in HDCP 2.0, the value of the initialvector is given by (r_(iv) XOR streamCtr)∥inputCtr. In this formula,streamCtr is equal to its immediately preceding value plus 1. AndinputCtr is equal to its immediately preceding value plus a numberobtained by adding 15 to the size of the entire segment of the PESpayload that accompanies the immediately preceding PES header of the ESPID concerned and dividing the resulting sum by 16. This value means thenumber (rounded up) of 16-byte encryption blocks obtained by dividingthe entire segment of the PES payload. The initial values of theencryption key and the initial vector are values calculated in the keyexchange processing according to the second copyright protection method.The initial values of streamCtr and inputCtr are “0.” At step S508, theencryption key and part of the initial vector are inserted into the PESheader. In HDCP 2.0, a PES_private_data field is inserted into the PESheader and inputCtr which is one constituent element of the initialvector and streamCtr are described. The second content receiver B canobtain an encryption key and an initial vector for decrypting thesegment of the PES payload correctly by combining information obtainedby the key exchange processing that was performed with the first contentreceiver A and PES header information received from the first contentreceiver A.

At step S509, irrespective of presence/absence of a PES header, theremaining segment of the PES payload is combined with the segment of thePES payload contained in the reception packet. At step S510, theremaining segment of the PES payload is AES-CTR-encrypted. The size ofthe encryption subject segment of the PES payload is calculated in thefollowing manner. The size of the adaptation filed excluding stuffingbytes (if the adaptation field consists of only stuffing bytes, thereceived packet is regarded as containing no adaptation field) issubtracted from total size (184 bytes) of the TS payload and theadaptation field. If the received packet contains a PES header, the sizeof the PES header is subtracted from total size of the TS payload andthe adaptation field. A maximum multiple of 16 (AES-CTR encryption keysize) that is smaller than the calculated TS packet data size isemployed as a size of the encryption subject segment of the PES payload.At step S511, an adaptation field is generated in which stuffing bytesare inserted so that the total size of the adaptation field, the PESheader (only when it is contained), and the encrypted segment of the PESpayload becomes equal to 184 bytes. At step S512, TS packet data isgenerated by combining the adaptation field, the PES header, and thesegment of the PES payload and the number n of generated TS packet datais incremented by 1.

If the size of the remaining segment of the PES payload is larger thanor equal to 176 bytes (a maximum multiple of 16 (AES-CTR encryption keysize) that is smaller than 184 bytes) (S513: yes), at step S514 data of176 bytes beginning from the head of the segment of the PES payload isAES-CTR-encrypted. At step S515, an adaptation field padded withstuffing bytes (8 bytes) is inserted before the encrypted PES payload togenerate one TS packet data. At step S516, the number n of generated TSpacket data is incremented by 1. The above steps are repeated (i.e., TSpacket data is generated and the number n of generated TS packet data isincremented by 1) until the size of the remaining segment of the PESpayload becomes smaller than 176 bytes (S513: no).

At step S517, the unencrypted segment of the PES payload data (smallerthan 176 bytes) is saved as a remaining segment of the PES payload. Theabove-described steps S501-S517 constitute step S418 shown in FIG. 4.

At step S419, n TS packets to be sent to the second content receiver Bare generated by inserting TS headers before the n TS packet datagenerated by the above process, respectively. The following values areset in respective fields of each TS header according to the MPEG2-TSformat. The PID of the TS header is made an ES PID. A value “1” is setin payload_unit_start_indicator of the TS header if the TS packet datacontains a PES header. Every time the number of TS packets increases,continuity_counter of the TS header is incremented by 1 if the TS packetdata contains a TS payload.

At step S420, n is added to the transmission packet counter. At stepS425, the generated packets are sent out. Then, the process returns tostep S403.

If the reception packet is a null packet (S412: yes), the count of thereception packet counter and that of the transmission packet counter arecompared with each other. If the count of the transmission packetcounter is smaller than that of the reception packet counter (S422: no),at step S 423 the reception packet is employed as it is as atransmission packet to be sent to the second content receiver B. At stepS424, the transmission packet counter is incremented by 1. At step S425,the generated packet is sent out. Then, the process returns to stepS403.

If the count of the transmission packet counter is larger than or equalto that of the reception packet counter (S422: yes), to adjust thedifference between the size of the received content data and that ofcontent data to be sent, no transmission packet is generated and thetransmission packet counter is not incremented. Then, the processreturns to step S403.

The generated transmission packets are sent to the second contentreceiver B sequentially.

The process that content data that is encrypted according to the firstcopyright protection method is received, then encrypted according to thesecond copyright protection method, and finally sent out by the firstcontent receiver A is summarized in a data flow diagram of FIG. 6. Eachencrypter manages a set of an encryption key and an initial vector foreach ES and AES-CTR-encrypts its PES payload. In FIG. 6, each block isassociated with a step (s) in FIG. 4 that mainly corresponds to it.

(Embodiment 2)

A second embodiment of the invention will be described below. Items thatare the same as in the first embodiment will not be described.

FIG. 9 shows the configuration of a copyright protection systemaccording to the second embodiment. Content data that is received by afirst content receiver A′ in the form of broadcasting such as digitalterrestrial broadcasting is locally encrypted and stored (recorded) inan HDD or a nonvolatile memory of the first content receiver A′ inadvance. The encrypted content stored in the HDD or the nonvolatilememory is decrypted by a local encryption key, encrypted by the secondcopyright protection method, and transmitted to the second contentreceiver B.

A flowchart of the second embodiment is obtained by replacing“reception” in the flowchart of FIG. 4 with “reading from the HDD or thenonvolatile memory.”

(Embodiment 3)

A third embodiment of the invention will be described below. Items thatare the same as in the first or second embodiment will not be described.

The third embodiment is such that the first or second embodiment of theinvention is applied to a case that, as in the Intel wireless display,the first content receiver A or A′ re-encodes a picture and sendsresulting content data to the second content receiver B. When a contentencrypted according to the first copyright protection method isreproduced on the full screen in the first content receiver A or A′according to a user manipulation and, at the same time, reproduced bythe second content receiver or when only a window in which a contentencrypted according to the first copyright protection method is beingreproduced is reproduced in the second content receiver B, as seen fromthe process described in the first or second embodiment, re-encodingneed not be performed in the first content receiver A or A′ during thisprocessing.

The embodiments provide an advantage that since PES payloads themselvesthat are encoded for the first copyright protection method areencrypted, quality degradation of the content and delay due tore-encoding can be prevented. In particular, increase in transfercontent size can be reduced to a minimum necessary value by deletingnull packets in the same number as the number of increased packets.

The above-described embodiments enable functioning of the followingsystems A-C:

A. A copyright protection method conversion system having a firstcontent receiver having a function of receiving a content from anetwork, digital broadcasting, or the like according to a firstcopyright protection method and a second content receiver having afunction of receiving the content that is transferred from the firstcontent receiver via a wired interface or a wireless interface accordingto a second copyright protection method and decoding the receivedcontent, characterized by the first content receiver which comprises aPID filter which processes a transport stream, a PAT/PMT analyzingmodule; a PMT generating module which is compatible with the secondcopyright protection method; encrypters for encrypting PES payloads bymanaging independent sets of an encryption key and an initial vector forrespective PIDs; and a transport stream packet generating module.

The second copyright protection method has the following features:

A-1. Content data (PES header and PES payload) is divided into pluralMPEG2-TS packets.

A-2. Only the segment of the PES payload is encrypted, and the size ofeach segment of the PES payload contained in each MPEG2-TS packet is amultiple of a fixed size. The remainder that is not included in theMPEG2-TS packet payload is padded with an adaptation field. (TheMPEG2-TS packet header and portions, not including the segment of thePES payload, of the MPEG2-TS packet payloads are not encrypted.)

A-3. In content data that consists of elementary streams, differentelementary streams are divided into MPEG2-TS packets in mixture and theset of an encryption key and an initial vector varies from oneelementary stream to another. Part of data relating to sets of anencryption key and an initial vector are contained in a PES header.

The first copyright protection method has the following features:

A-4. Content data (PES header and PES payload) is divided into pluralMPEG2-TS packets.

A-5. When a PES payload is divided into plural MPEG2-TS packets, thesize of the segment of the PES payload contained in each MPEG2-TS packetpayload is not necessarily a multiple of a fixed size unlike in thesecond copyright protection method.

B. A copyright protection method conversion system characterized in thatif the number of MPEG2-TS packets that comply with the second copyrightprotection method is larger than or equal to the number of MPEG2-TSpackets that comply with the first copyright protection method and theMPEG2-TS packets that comply with the first copyright protection methodcontain null packets, the MPEG2-TS packets are transferred according tothe second copyright protection method with the null packets deletedwhich are equal in number to increased packets.

C. A copyright protection method conversion system characterized in thatthe second copyright protection method is a standard that succeeds HDCP2.0.

According to the embodiments, the following advantages are obtained in acopyright protection conversion system which is characterized by an HDCPoutput that is free of degradations, because it is provided with a PIDfilter module which processes a transport stream, an encryptionprocessing module for encrypting PES payloads by managing independentsets of an encryption key and an initial vector for respective PIDs; atransport stream packet generating module, and a content transmitter:

(1) When a copyright-protected content that complies with the firstcopyright protection method is transferred according to the secondcopyright protection method, delay due to re-encoding of the content canbe prevented.

(2) When a copyright-protected content that complies with the firstcopyright protection method is transferred according to the secondcopyright protection method, the content can be transmitted to a secondcontent receiver with no degradations.

(3) Even where a copyright-protected content that complies with thefirst copyright protection method cannot be decoded by a first contentreceiver itself, it can be decoded and viewed by another apparatus.

In particular, increase in transfer content size can be made a minimumnecessary value by deleting null packets that are equal in number toincreased packets.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel methods and systems describedherein may be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the methods andsystems described herein may be made without departing from the spiritof the inventions. The accompanying claims and their equivalents areintended to cover such forms or modifications as would fall within thescope and spirit of the inventions.

What is claimed is:
 1. An information processing apparatus comprising: acontent acquirer configured to receive or store a content complying witha first copyright protection; a filter configured to acquire packetidentifications (PIDs) from headers of packets of the content toidentify types of the packets; an analyzer configured to analyze aprogram association table (PAT) to acquire a first program map table(PMT) PID and analyze the first PMT to acquire an elementary system (ES)PID; a first generator configured to generate a second PMT complyingwith a second copyright protection, by adding a descriptor indicatingthat the content is encrypted according to the second copyrightprotection to the first PMT, to generate first packets; an encrypterconfigured to extract data having a first size from packetizedelementary stream (PES) payloads and to encrypt the extracted PESpayloads with respect to a second size by using an encryption key and aninitial vector, the first size being equal to the integral multiple ofthe second size; a second generator configured to generate secondpackets by inserting an adaptation field padded with stuffing bytes tothe encrypted PES payloads; and a transmitter configured to transmit thefirst packets and the second packets, wherein the filter is configuredto identify types of the packets of the first PMT based on the PID ofthe first PMT acquired by analyzing the PAT and to identify types of thepackets of the ES based on the ES PID acquired by analyzing the PMT. 2.The information processing apparatus of claim 1, wherein: the first sizeis 176 bytes; the second size is 16 bytes; and the adaptation field has8 bytes.
 3. The information processing apparatus of claim 2, wherein thePES payloads are divided into a plurality of packets.
 4. The informationprocessing apparatus according to claim 3, the contents includes one ofthe PES payloads having a size not equal to the integral multiple of 16bytes.
 5. The information processing apparatus of claim 3, furthercomprising a decoder configured to decode the contents; and a displayconfigured to display the decoded contents.
 6. An information processingmethod in an information processing apparatus comprising: receiving orstoring a content according to a first copyright protection method;acquiring packet identification (PIDs) from headers of packets of thecontent to identify types of the packets; analyzing a programassociation table (PAT) to acquire a first program map table (PMT) PIDand analyze the first PMT to acquire an elementary stream (ES) PID;generating a second PMT according to a second copyright protectionmethod, by adding a descriptor indicating that the content is encryptedaccording to the second copyright protection method to the first PMT, togenerate first packets; extracting data having a first size formpacketized elementary stream (PES) payloads and encrypting the extractedPES payloads with respect to a second size by using an encryption keyand an initial vector, the first size being equal to the integralmultiple of the second size; generating second packets by inserting anadaptation field padded with stuffing bytes to the encrypted PESpayloads; and sending the first packets and the second packets, whereintypes of the packets of the first PMT is identified based on PID of thefirst PMT acquired by analyzing the PAT, and types of the packets of theES is identified based on ES PID acquired by analyzing the PMT.
 7. Theinformation processing method of claim 6, wherein: the first size is 176bytes; the second size is 16 bytes; and the adaptation field has 8bytes.
 8. The information processing method of claim 7, wherein the PESpayloads are divided into a plurality of packets.
 9. The informationprocessing method of claim 8, wherein the contents includes one of thePES payloads having a size being not equal to the integral multiple of16 bytes.
 10. The information processing method of claim 8, furthercomprising: decoding the contents; and displaying the decoded contents.